external/bsd/llvm/dist/clang/lib/AST/ParentMap.cpp

   1 //===--- ParentMap.cpp - Mappings from Stmts to their Parents ---*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 //  This file defines the ParentMap class.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/AST/ParentMap.h"
  15 #include "clang/AST/Decl.h"
  16 #include "clang/AST/Expr.h"
  17 #include "clang/AST/ExprCXX.h"
  18 #include "llvm/ADT/DenseMap.h"
  19
  20 using namespace clang;
  21
  22 typedef llvm::DenseMap<Stmt*, Stmt*> MapTy;
  23
  24 enum OpaqueValueMode {
  25   OV_Transparent,
  26   OV_Opaque
  27 };
  28
  29 static void BuildParentMap(MapTy& M, Stmt* S,
  30                            OpaqueValueMode OVMode = OV_Transparent) {
  31
  32   switch (S->getStmtClass()) {
  33   case Stmt::PseudoObjectExprClass: {
  34     assert(OVMode == OV_Transparent && "Should not appear alongside OVEs");
  35     PseudoObjectExpr *POE = cast<PseudoObjectExpr>(S);
  36
  37     // If we are rebuilding the map, clear out any existing state.
  38     if (M[POE->getSyntacticForm()])
  39       for (Stmt::child_range I = S->children(); I; ++I)
  40         M[*I] = nullptr;
  41
  42     M[POE->getSyntacticForm()] = S;
  43     BuildParentMap(M, POE->getSyntacticForm(), OV_Transparent);
  44
  45     for (PseudoObjectExpr::semantics_iterator I = POE->semantics_begin(),
  46                                               E = POE->semantics_end();
  47          I != E; ++I) {
  48       M[*I] = S;
  49       BuildParentMap(M, *I, OV_Opaque);
  50     }
  51     break;
  52   }
  53   case Stmt::BinaryConditionalOperatorClass: {
  54     assert(OVMode == OV_Transparent && "Should not appear alongside OVEs");
  55     BinaryConditionalOperator *BCO = cast<BinaryConditionalOperator>(S);
  56
  57     M[BCO->getCommon()] = S;
  58     BuildParentMap(M, BCO->getCommon(), OV_Transparent);
  59
  60     M[BCO->getCond()] = S;
  61     BuildParentMap(M, BCO->getCond(), OV_Opaque);
  62
  63     M[BCO->getTrueExpr()] = S;
  64     BuildParentMap(M, BCO->getTrueExpr(), OV_Opaque);
  65
  66     M[BCO->getFalseExpr()] = S;
  67     BuildParentMap(M, BCO->getFalseExpr(), OV_Transparent);
  68
  69     break;
  70   }
  71   case Stmt::OpaqueValueExprClass: {
  72     // FIXME: This isn't correct; it assumes that multiple OpaqueValueExprs
  73     // share a single source expression, but in the AST a single
  74     // OpaqueValueExpr is shared among multiple parent expressions.
  75     // The right thing to do is to give the OpaqueValueExpr its syntactic
  76     // parent, then not reassign that when traversing the semantic expressions.
  77     OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(S);
  78     if (OVMode == OV_Transparent || !M[OVE->getSourceExpr()]) {
  79       M[OVE->getSourceExpr()] = S;
  80       BuildParentMap(M, OVE->getSourceExpr(), OV_Transparent);
  81     }
  82     break;
  83   }
  84   default:
  85     for (Stmt::child_range I = S->children(); I; ++I) {
  86       if (*I) {
  87         M[*I] = S;
  88         BuildParentMap(M, *I, OVMode);
  89       }
  90     }
  91     break;
  92   }
  93 }
  94
  95 ParentMap::ParentMap(Stmt *S) : Impl(nullptr) {
  96   if (S) {
  97     MapTy *M = new MapTy();
  98     BuildParentMap(*M, S);
  99     Impl = M;
 100   }
 101 }
 102
 103 ParentMap::~ParentMap() {
 104   delete (MapTy*) Impl;
 105 }
 106
 107 void ParentMap::addStmt(Stmt* S) {
 108   if (S) {
 109     BuildParentMap(*(MapTy*) Impl, S);
 110   }
 111 }
 112
 113 void ParentMap::setParent(const Stmt *S, const Stmt *Parent) {
 114   assert(S);
 115   assert(Parent);
 116   MapTy *M = reinterpret_cast<MapTy *>(Impl);
 117   M->insert(std::make_pair(const_cast<Stmt *>(S), const_cast<Stmt *>(Parent)));
 118 }
 119
 120 Stmt* ParentMap::getParent(Stmt* S) const {
 121   MapTy* M = (MapTy*) Impl;
 122   MapTy::iterator I = M->find(S);
 123   return I == M->end() ? nullptr : I->second;
 124 }
 125
 126 Stmt *ParentMap::getParentIgnoreParens(Stmt *S) const {
 127   do { S = getParent(S); } while (S && isa<ParenExpr>(S));
 128   return S;
 129 }
 130
 131 Stmt *ParentMap::getParentIgnoreParenCasts(Stmt *S) const {
 132   do {
 133     S = getParent(S);
 134   }
 135   while (S && (isa<ParenExpr>(S) || isa<CastExpr>(S)));
 136
 137   return S;
 138 }
 139
 140 Stmt *ParentMap::getParentIgnoreParenImpCasts(Stmt *S) const {
 141   do {
 142     S = getParent(S);
 143   } while (S && isa<Expr>(S) && cast<Expr>(S)->IgnoreParenImpCasts() != S);
 144
 145   return S;
 146 }
 147
 148 Stmt *ParentMap::getOuterParenParent(Stmt *S) const {
 149   Stmt *Paren = nullptr;
 150   while (isa<ParenExpr>(S)) {
 151     Paren = S;
 152     S = getParent(S);
 153   };
 154   return Paren;
 155 }
 156
 157 bool ParentMap::isConsumedExpr(Expr* E) const {
 158   Stmt *P = getParent(E);
 159   Stmt *DirectChild = E;
 160
 161   // Ignore parents that don't guarantee consumption.
 162   while (P && (isa<ParenExpr>(P) || isa<CastExpr>(P) ||
 163                isa<ExprWithCleanups>(P))) {
 164     DirectChild = P;
 165     P = getParent(P);
 166   }
 167
 168   if (!P)
 169     return false;
 170
 171   switch (P->getStmtClass()) {
 172     default:
 173       return isa<Expr>(P);
 174     case Stmt::DeclStmtClass:
 175       return true;
 176     case Stmt::BinaryOperatorClass: {
 177       BinaryOperator *BE = cast<BinaryOperator>(P);
 178       // If it is a comma, only the right side is consumed.
 179       // If it isn't a comma, both sides are consumed.
 180       return BE->getOpcode()!=BO_Comma ||DirectChild==BE->getRHS();
 181     }
 182     case Stmt::ForStmtClass:
 183       return DirectChild == cast<ForStmt>(P)->getCond();
 184     case Stmt::WhileStmtClass:
 185       return DirectChild == cast<WhileStmt>(P)->getCond();
 186     case Stmt::DoStmtClass:
 187       return DirectChild == cast<DoStmt>(P)->getCond();
 188     case Stmt::IfStmtClass:
 189       return DirectChild == cast<IfStmt>(P)->getCond();
 190     case Stmt::IndirectGotoStmtClass:
 191       return DirectChild == cast<IndirectGotoStmt>(P)->getTarget();
 192     case Stmt::SwitchStmtClass:
 193       return DirectChild == cast<SwitchStmt>(P)->getCond();
 194     case Stmt::ReturnStmtClass:
 195       return true;
 196   }
 197 }
 198